RNA interference (RNAi) is a form of post-transciptional gene silencing mediated by short non-coding RNA molecules. RNAi is thought to act via specific base pairing with complementary target nucleic acid resulting in the degradation of the target molecule or inhibition of its translation. There are a wide range of RNA classes and pathways that can result in down-regulation or gene silencing.
Previous studies have shown that inhibitory RNA molecules may be useful in the treatment of certain diseases, including cancer. These studies have focused on directly killing tumour cells by silencing particular genes involved in cancer maintenance and development. However, to be effective, the inhibitory RNA molecules must be delivered and expressed at a cytotoxic level in each tumour or disease cell. Accordingly, very large dosages of inhibitory RNA molecules need to be administered to achieve a reasonable amount of tumour reduction or disease control. Very little success has been achieved in the effective reduction of tumour cells or disease using this method.
Accordingly, there is a need for improved methods for effectively using inhibitory nucleic acids to treat disease, that do not necessarily rely on large dosages of the inhibitory nucleic acid or direct killing of every target cell to be effective.